2 Shot to Death, 7 Wounded at San Marino Grad Party : Crime: A victim says assailants returned after an argument. Flyers advertised the event, which drew 100.

Two young people wielding semiautomatic weapons sprayed gunfire through a high school graduation party at a home in affluent San Marino early Sunday, killing two students and wounding seven other people, authorities said.

A 14-year-old boy died in the back yard of a house valued at nearly $1 million on a cul-de-sac in northeast San Marino. He was identified as David Hang by the Los Angeles County coroner’s office and by a distraught woman who stopped by the home Sunday afternoon and identified the dead boy to reporters as her son.

Another victim, who died at an undisclosed hospital, was identified as Dennis Buan, 18, of South Pasadena, said Lt. Deborah Peterson of the coroner’s office.

Authorities said the wounded were between 17 and 21 years old. One, identified by friends as Oliver Chu, 18, was in serious condition Sunday, and six others were listed in stable condition. One teen-ager was treated and released.

Violence is rare in San Marino, a well-to-do city of 13,000 northeast of Los Angeles.

“Our neighborhoods are not neighborhoods now,” said a woman passing by the bullet-riddled house Sunday. “. . . No one knows what’s going to happen.”

The assailants were a young man and a young woman who fired semiautomatic weapons into the crowd at 1 a.m., according to a San Marino High School student who was wounded in the fusillade.

About 100 had shown up at the party, an “End of the Year Jam” that charged $2 at the door. Flyers advertising the event said it would run “from 7:30 to whenever the pigs come.”

On the sidewalk in front of the house Sunday, a party-goer who identified himself as Tom said, “There’s always parties like this in San Marino every weekend, huge rages. But they always get broken up” by police.

Some young guests said the host, high school student Frank Chen, had not given many parties but had taken the precaution of stationing someone at the door with a hand-held metal detector to screen party-goers.

A high school student who was wounded at the party and asked that his name not be used described the attack:

“I thought I was going to die, because it was just rat-a-tat-tat-tat-tat. They didn’t say anything. I just heard my friends yell, ‘Duck! Duck!’ There were eight of us all in a row, and we all got shot.”

The young man, still wearing the same bloodstained pants Sunday afternoon, said he had been shot in the buttocks. He described an argument at the party involving the disc jockey and several people, two of whom later came back shooting.

After the guests argued with the disc jockey, they reassured others that “everything was OK,” the teen-ager said. “But they were just fooling us. They were setting us up for the slaughter.”

Deputies said eight to 12 suspects, who had left the party after the dispute, returned in three cars. The two who did the shooting went into the back yard and “opened fire at the party-goers, spraying the exterior and the interior of the house,” deputies said.

The parents of the party’s young host were asleep in the house at the time, deputies added.

The wounded student said he and several friends were playing cards in the back yard “when all of a sudden they came back.” He said the man carried what he thought was an AK-47 assault rifle, and the young woman had a pistol.

Deputies said both were believed to be carrying semiautomatic handguns.

As the pair were shooting, deputies said, other people were damaging cars parked in front of the home.

“It was a gang thing,” the wounded student told reporters when he returned to the house with his parents Sunday afternoon after being released from the hospital. “I don’t want any pictures. I don’t want any identification, because I’m afraid of retaliation.

“I’ve just seen one of my friends shot in the intestines, and one was shot in the chest. And we’re all very scared.”

One San Marino youth, who said he lent equipment to one of the party’s two 17-year-old disc jockeys, disputed the statement that an argument had prompted the shooting. The youth, who declined to give his name, said the disc jockey blamed the shooting on “some gang” that began making trouble.

Students who came by the house Sunday said that Hang, one of the dead, was a freshman at San Marino High and that Buan was a senior at South Pasadena High School. A small group of Hang’s friends laid a bouquet of flowers at the place in the back yard where he had died.

No arrests had been made as of midday Sunday. The suspects are “predominantly Asian males and females,” deputies said.

“It was a messed-up party,” said Vincent Liu, 17, of San Gabriel. “I knew something was going to happen.” Liu said he drove to the party about 10 p.m. but was challenged in the street by a group of hostile youths who said they were from Burbank. Liu said he turned around and left to avoid trouble.

Investigators said the three vehicles involved were a white Mitsubishi Tredia, about a 1985 model; a red 1990 or 1991 Honda Civic hatchback, and a light gray, white or beige 1989 or 1990 Honda Civic four-door sedan. The Honda sedan collided with another car near the shooting scene and might be damaged, investigators said.

Property tax records show that the site of the party is a 13-room, 3,600-square-foot home with a swimming pool, belonging to Fu Hsing and Jyu Yuan Chen, who bought the house in 1990 for $1.025 million.

San Marino Police Sgt. F. S. Beeal said his department is not prepared to investigate a crime of this nature, so the investigation was turned over to the Sheriff’s Department.

Incidents such as this, he said, “are getting more frequent” in San Marino.

The city of expensive homes was in the news spotlight last month, when a swimming pool excavation unearthed human remains--the first apparent homicide investigated in San Marino since the 1990 fatal shooting of a Taiwanese businessman in the driveway of his Bradbury Road home.

In December, a San Marino man suspected in a murder-for-hire plot against his wife was shot and killed in the police station by a detective he had just stabbed.

Richard August, 41, had pulled a knife from his waistband and stabbed the detective after he was arrested on suspicion of conspiracy in his wife’s attempted murder, police said.

San Marino residents pride themselves on their good school system and manicured lawns. The community founded by old California families south of Pasadena has become home to a new Asian American gentry virtually overnight.

An American-born real estate agent of Asian descent described the community two years ago as being “like Beverly Hills to Asians.”

The new Asian residents have brought a passion for education to the community that has helped make a first-rate school system even better, school officials said.

The city is the birthplace and boyhood home of World War II tank commander Gen. George S. Patton and home to the Huntington Library, which houses a renowned collection including Thomas Gainsborough’s “Blue Boy,” Thomas Lawrence’s “Pinkie,” a Gutenberg Bible, a manuscript of Chaucer’s “Canterbury Tales” and many other works of art and literature.

Times staff writer Vicki Torres contributed to this story.